Preprints
https://doi.org/10.5194/egusphere-2024-2675
https://doi.org/10.5194/egusphere-2024-2675
18 Sep 2024
 | 18 Sep 2024

Simulated ocean oxygenation during the interglacials MIS 5e and MIS 9e

Bartholomé Duboc, Katrin J. Meissner, Laurie Menviel, Nicholas K. H. Yeung, Babette Hoogakker, Tilo Ziehn, and Matthew Chamberlain

Abstract. Recent studies investigating future warming scenarios have shown that the ocean oxygen content will continue to decrease over the coming century due to ocean warming and changes in oceanic circulation. However, significant uncertainties remain regarding the magnitude and patterns of future ocean deoxygenation. Here, we simulate ocean oxygenation with the ACCESS ESM1.5 model during two past interglacials that were warmer than the preindustrial climate, the Last Interglacial (Marine Isotope Stage (MIS) 5e, ~ 129–115 ka) and MIS 9e (~ 336–321 ka). While orbital parameters were similar during MIS 5e and MIS 9e, with lower precession, higher eccentricity and higher obliquity than pre-industrial, greenhouse gas radiative forcing was highest during MIS 9e. We find that the global ocean is overall less oxygenated in the MIS 5e and MIS 9e simulations compared to the preindustrial control run and that oxygen concentrations are more sensitive to changes in the distribution of incoming solar radiation than to differences in greenhouse gas concentrations. Large regions in the Mediterranean Sea are hypoxic in the MIS 5e simulation, and to a lesser extent in the MIS 9e simulation, due to an intensification and expansion of the African Monsoon, enhanced river run-off and resulting freshening of surface waters and stratification. Upwelling zones off the coast of North America and North Africa are weaker in both simulations compared to the preindustrial control run, leading to less primary productivity and export production. Antarctic Bottom Water is less oxygenated, while North Atlantic Deep Water and the North Pacific Ocean at intermediate depths are higher in oxygen content. All changes in oxygen concentrations are primarily caused by changes in ocean circulation and export production and secondarily by changes in temperature and solubility.

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Bartholomé Duboc, Katrin J. Meissner, Laurie Menviel, Nicholas K. H. Yeung, Babette Hoogakker, Tilo Ziehn, and Matthew Chamberlain

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-2675', Anonymous Referee #1, 22 Oct 2024
  • RC2: 'Comment on egusphere-2024-2675', Anonymous Referee #2, 29 Oct 2024
  • RC3: 'Comment on egusphere-2024-2675', Anonymous Referee #3, 29 Oct 2024
Bartholomé Duboc, Katrin J. Meissner, Laurie Menviel, Nicholas K. H. Yeung, Babette Hoogakker, Tilo Ziehn, and Matthew Chamberlain

Data sets

Simulated ocean oxygenation during the interglacials MIS 5e and MIS 9e Nicholas K.H. Yeung and Bartholomé Duboc https://doi.org/10.26190/unsworks/30420

Bartholomé Duboc, Katrin J. Meissner, Laurie Menviel, Nicholas K. H. Yeung, Babette Hoogakker, Tilo Ziehn, and Matthew Chamberlain

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Short summary
We use an Earth System Model to simulate ocean oxygen during two past warm periods, the Last Interglacial (~129–115 ka) and Marine Isotope Stage (MIS) 9e (~336-321 ka).  The global ocean is overall less oxygenated compared to the preindustrial simulation. Large regions in the Mediterranean Sea are oxygen deprived in the Last Interglacial simulation, and to a lesser extent in the MIS 9e simulation, due to an intensification and expansion of the African Monsoon and enhanced river run-off.